Everyone can think of a favorite song or two (or three) which can easily be translated into a fantasy rpg concept, be it an item, plot, location, or what have you. Just take the lyrics of your favorite real-life ditty, and go from there!

Bee Guardian

A fey spirit masks itself as a bee which investigates all who travel within a specific section of the forest. Any the bee finds worthy are allowed to see the hidden opening into the fey kingdom, just off of the trail. Any deemed unworthy see only the bee, buzzing around around them momentarily before moving on.